The Westside Transport Box on Ocean Beach in S.F. will mark an expected 14-inch rise in sea level by 2050.

Photo: Michael Macor, The Chronicle

The Westside Transport Box on Ocean Beach in S.F. will mark an...

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Posts from the parking lot above, at Sloat Blvd. and the Great Highway, along Ocean Beach, in San Francisco, Ca., on Thursday April 5, 2012, have fallen onto the beach below as the cliff has eroded. Ocean Beach draws more than 300,000 surfers, cyclists and visitors annually, making it one of San Francisco's most beloved natural open spaces. It will also be the city's first real test in responding to the effects of climate change. By 2050, the sea level will rise 14 inches, meaning the coast and the major wastewater and stormwater infrstructure embedded into it will be seriously eroded. A new plan from the San Francisco Planning Urban and Research Association, the final version of which will be released in April, lays out a long-term vision for the area.

The California coast probably will never see a storm as violent as the one that pounded the East Coast, but the future for Westerners will be rife with environmental problems caused by global warming, including torrential rain, flooding, fire and drought, climate experts say.

The issue of human-caused climate change leaped to the fore this week when New York Gov. Andrew Cuomo urged people to take action against a phenomenon he contends was behind the disastrous effects of superstorm Sandy, which caused dozens of deaths and widespread destruction.

The capricious climate is fixing to make trouble here too, experts say, particularly along the waterfront. Scientific forecasts show that water levels in San Francisco Bay could rise 16 inches or more by 2050, inundating shoreline habitat and infrastructure.

"The Bay Area and California are very prone to flood damage," said Chris Field, director of the global ecology department at the Carnegie Institution for Science at Stanford University. "We do face a real risk of flooding during winter storms coupled with high sea level. If we get a big rainstorm combined with high sea level and high tide, we have a risk for a tremendous amount of damage."

Field, who is co-chair of a working group for the U.N. Intergovernmental Panel on Climate Change, said sea levels have risen 6 inches over the past century and could rise more than 2 feet over the next 100 years if nothing is done to curb emissions of carbon dioxide from fossil fuels - the chief gas blamed for global warming.

That could transform California's bad storms into really awful tempests.

Hybrid storms

Jan Null, a meteorologist for Golden Gate Weather Services, said hybrid storms somewhat similar to Sandy, which was a strange combination of a hurricane and nor'easter, are possible along the West Coast. It happened in 1962 when a storm rolled in from the Gulf of Alaska and took on moisture from Typhoon Freda, causing, among other things, four days of rainouts during the World Series between the San Francisco Giants and the New York Yankees.

"We've had other storms where it was the same sort of scenario," Null said. "They tend to be wetter than normal," but not as bad as a hurricane.

Storms aren't the only issue, though. Sea surface temperatures are rising and are expected to continue to go up this century. As a result, Arctic sea ice shrank this summer to its smallest size ever, covering almost half the area it did 30 years ago when satellites and submarines began measurements.

It is an alarming problem because ice reflects heat and solar energy back into space. Less ice cover means more heat energy is absorbed by the ocean, which warms and melts more ice.

The Arctic warming influences weather patterns to the south, including the Bay Area. Meanwhile, the sea becomes more acidic, which could result in the loss of major fisheries along the West Coast and elsewhere, according to environmental scientists.

Shrinking snowpack

The weather pattern changes are also likely to cause the Sierra snowpack to shrink over the next 30 years, according to climate scientists. The amount of annual snow has already declined over three-quarters of the Western United States, an area that includes Montana, Wyoming and New Mexico, according to Scripps Research Institute researchers.

A reduction in snowmelt, which is what fills California's reservoirs and provides drinking water and agricultural irrigation throughout the state, could lead to disastrous water shortages, reductions in hydropower production, destruction of river ecosystems and economic limbo for ski-dependent communities.

Wine production, which can be negatively impacted by even the smallest temperature changes, could be hit hard, and salt from ocean water creeping up into the Sacramento-San Joaquin River Delta could impact crops in the Central Valley. Without enough snowmelt, California's reservoirs could be tempted to overload with rainwater in the winter, increasing the flood risk and putting even more pressure on the creaky system of levees that now protect the delta.

Researchers say early snowmelt would also leave California bone-dry during the summer, which would lead to bigger, more frequent fires, according to numerous studies. A 2007 study by NASA predicted lightning would increase by about 6 percent in future years, a scenario that, given everything else, would be like a match to kindling.

Time to prepare

The good thing is that there is still time to prepare.

"Climate change is going to continue, and there are a lot of things we can do to manage the changes that are going to occur," Field said. Those include "better preparation, infrastructure improvements, warning systems and better disaster response."

California is one of only nine states that have developed strategies and implemented policies to deal with water shortages, droughts, a shrinking snowpack and other problems associated with climate change, a Natural Resources Defense Council report found earlier this year. Agriculture officials are experimenting with drought-tolerant crop varieties, and wetlands restoration is a growing trend around San Francisco Bay.

On Nov. 14, the California Air Resources Board will implement America's first full-fledged cap-and-trade program for cutting carbon dioxide emissions, a program that officials hope will lead to a clean energy revolution.

"The damage that occurs from a weather disaster is a function not only of the event, but of the infrastructure and vulnerability of the people," Diffenbaugh said. "With climate change we can expect the hazards to change, some in predictable ways and some in unpredictable ways. Planning can be important in the amount of damage that eventually occurs."